A seat belt system for restraining a seated prisoner in a law enforcement vehicle ordinarily includes seat belt webbing, a seat belt buckle, and a seat belt retractor. A locking tongue on the webbing is releasably lockable in the buckle when the webbing has been extracted from the retractor and moved to a position in which shoulder and lap belt sections of the webbing extend across the prisoner. If the vehicle experiences a crash, a locking mechanism in the retractor blocks further extraction of the webbing. The webbing then restrains movement of the prisoner to protect the prisoner from a forceful impact with parts of the vehicle as a result of the crash.
Often, however, seat belts in police vehicles are simply not used. This is due to the location of the belt system within a police vehicle, which places the retractor mounted outboard of the prisoner and the buckle is positioned inboard of the prisoner. Police officers are under considerable risk of injury should they belt the prisoner. Injuries to the police officer can be caused by the prisoner biting, kicking, or head butting the police officer while the officer reaches over the prisoner to buckle him. As such, the belt in police vehicles are rarely used. As a result, a significant liability risk exists for municipalities which may be found responsible for injuries caused to a prisoner during a vehicle accident.
Seat belt retractors fall into two broad categories. The first being an emergency locking retractor (ELR) which is activated only during an emergency to prevent protraction of the seat belt (webbing) wound about a spool of the retractor. This type of retractor includes various known sensors such as a web sensor with initiates the locking of the spool when the webbing is pulled at a rate above a designated level and a vehicle or inertia sensor sensitive to levels of vehicle deceleration to bring the spool into a locked condition. The second type of retractor is one which is brought into a locked condition after a determinable length of webbing has been protracted. Once this length of webbing has been protracted, the retractor spool is automatically in its locked condition preventing further protraction of the webbing. This type of retractor is often referred to as an automatic locking retractor (ALR). The ALR retractor is reset once the webbing is fully retracted upon the spool. The ALR function has also been incorporated into an ELR retractor. This type of retractor includes a mode switching mechanism to switch the retractor from operating as an ELR to one that operates as an ALR retractor.
This mode switching mechanism can take many forms such as a feeler bar that rides upon the webbing coiled upon the spool. As the webbing is protracted, the feeler bar rotates inwardly and at some angle, indicative of an amount of webbing protracted from the retractor. The feeler bar causes a lock pawl to be moved into engagement with the lock teeth of the retractor. A more complex mode switching mechanism can be realized using a series of gears which rotate with the spool and, at a predetermined position, one or more of these gears activate a lever to cause a lock pawl to engage a lock teeth of the retractor.
This ELR/ALR retractor operates as an ELR retractor during an emergency and acts as an ALR once the seat belt webbing has been protracted a determinable length. A retractor with an ALR feature has proven useful in securing a child seat to the vehicle seat. After the child seat is in place upon the vehicle seat, the webbing is fully protracted from the retractor, activating the mode switching mechanism. After the latch plate (also referred to as a tongue) is secured into its buckle the webbing is released and rewound into the retractor by its rewind spring. Once this occurs, the webbing is pulled tight about the child seat. Since the retractor is now in its ALR mode of operation, the webbing is prevented from protracting during an emergency and, as such, the child seat is held securely upon the seat.